Grooved slip ring



Aug. 10, 1948. D. SPRAGUE GROOVED SLIP RING File? Nov. 16, 1944 COLLECTOR RING INVENTOR. DESMOND SPRAGUE BY V TORNEY Patented Aug. 10, 1948 GROOVE!) SLIP RING Desmond Sprague, West Caldwell, N. 1., assignmto Curtis-Wright Corporation, a corporation of Delaware Application November 18, 1944, Serial No. 563,640

2 Claims. 1

The invention relates in general to an improvement in the unit which forms the slip ring-brush parts or a current collecting device, and the invention specifically relates to an improvement in the brush contacting faces of such rotating slip rings.

In devices of this character, it has been known that an extremely thin film of insulating air collects between the brush and the surface of the collector ring engaged thereby, and that the presence of any such air film seriously interferes with the desired continuity of contact between the brush and this surface. Attempts have been made to vent this air from the joint between the brush and slip ring, but any device so operating cannot remedy the difficulty, apparently because the air is held to the ring and brush by adhesion forces greater than any flow forces present which might tend to displace the air.

Further, it has been found that extremely minute foreign particles, presumably loose granular matter ground off the brushes by the slip rings or ground off the slip rings by the brushes, collect in the joint between the brush and slip ring surfaces with resultant interference between brush and slip ring contact.

The primary object of the invention is to provide a simple construction of brush and slip ring which will positively remove, or at least minimize, the deleterious effect of the air film, and which will at the same time tend to sweep from the contact surf-aces between brush and slip ring any of the fine ground material caught therebetween. Broadly, these objects are attained simply by providing one or more shallow helical grooves in the perimeter or other surface of the slip ring on which the brush rides.

Various other objects and advantages of the invention will be in part obvious from an inspection of the accompanying drawings and in part will be more fully set forth in the following particular description of one form of slip ring embodying the invention, and the invention also consists in certain new and novel features of construction and combination of parts hereinafter set forth and claimed.

In the drawing:

Figure 1 is a side view in elevation of a part of a slip ring embodying a preferred embodiment of the invention.

Figure 2 is a view in end elevation of the complete collector ring and brush member shown in Figure 1, and

Figure 3 is an enlarged detail view in cross section of the brush member and that portion of the slip ring which is engaged thereby with the showing of the grooves much enlarged.

In the several figures of the drawing there is shown a slip ring A mounted for rotary movement and a relatively fixed brush B engaging the cylindrical surface C of the ring A, and otherwise the disclosure is intended to illustrate conventional forms of current collecting devices.

The surface C is provided with two helical grooves 10 and ll disposed on opposite sides of a medial plane a-b perpendicularto the axis of rotation cd of the slip ring. One of the grooves I0 is a right hand helical groove when viewing the disclosure as turning in a clockwise direction as indicated by the several arrows. The other groove II is a left hand helical groove. The grooves meet in a V-shaped portion l2 in the medial plane 11-!) and have their discharge ends l3 and I4 open respectively at adjacent edges l5 and I6 of the ring. It will be understood from this construction that the grooves are. arranged with a. looking-glass symmetry and each extends axially from the center outwardly towards its adjacent side. The grooves are very small in cross section and in the illustrated showing are semicircular in cross section. The spaces I1 between adjacent turns of the grooves are smooth and relatively wide compared with the width of the grooves.

In operation, and assuming that the ring is turning at the high speed at which such rings customarily turn, the surface thereof which is engaged by the brush member rotates past the brush member as is well known in devices of this character. Any air or foreign solid matter which may be adhering to the contact surfaces provided at any instant of time between the ring and brush is swept laterally off the surface into the atmosphere. Presumably the air and fine particles are swept off the smooth interengaging surfaces into the closely adjacent portions of the grooves and are swept by the relative rotation of the parts outwardly of the ring, and thus any material which might otherwise tendto accumulate between the ring and brush is constantly re- 1. In a current collecting device, the combination of a rotatable slip ring and a coacting brush member. the surface of the ring with which the brush member contacts provided with a pair of shallow helical grooves of semi-circular form in cross section, one of the grooves forming a right hand helical groove extending from the medial plane of the slip ring outwardly to its adjacent edge, and the other forming a left hand helical groove extending from the medial plane outwardly to the opposite edge of the slip ring. the inner ends of said grooves meeting at the medial plane in the form of a V pointing in the direction of rotation of the slip ring and the outer ends of the grooves being beyond the adjacent end of the brush member and exposed to the external atmosphere. whereby said grooves during ring rotation relative to the brush member may carry foreign matter from the ring medial plane toward both ring edges for issue thereat.

2. As an article of manufacture, a slip ring for a current collecting device having a brush engaging peripheral surface, said surface having a pair of helical grooves of opposite hand disposed side-hy-side in the surface, having their outer ends open at the opposite edges of the ring and their inner ends intercommunicating with each other substantially in the medial plane of the ring, said ring being adapted for rotation in a direction to lead matter in said grooves from the center of the ring surfaces toward its edges.

DEBMOND SPRAGUE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 15 Number Name Date 1,428,863 Smith Sept. 12, 1922 1,495,780 Eschholz et al May 27, 1924' 2,044,180 Newton June 16, 1936 FOREIGN ra'ran'rs Number Country Date 317,424 Great Britain Aug. 16, 1929 

